There actually is no average time for any claim. The 800# will give you a quote of the national average, however each claim gets worked in the order received. And each VAro has different work schedules. ALso depending upon your claim, it may get shuffled around quite a bit before a decision is reached.

You can call daily, send out iris weekly, write your Congressman monthly and it still will get done when it gets finished. The VA is not like a normal business that actually gets things done within there established time frame .
Even the folks working on your claim couldn't give an estimate. There are so many hands your file goes to, it won't be known until the actual letter has been printed and mailed with a possible retro hitting your bank.

I have been waiting for 14 months(428)days on my claim. My claim is still in the Gathering Information Phase even though all my information is in. I hope I am still alive and kicking when and if it is done!